易溃散性氧化铝基陶瓷型芯的制备

发布时间：2018-03-01 15:38

本文关键词： 氧化铝陶瓷型芯溃散性酚醛树脂　出处：《华南理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：氧化铝基陶瓷型芯耐高温、化学稳定性好、高温抗蠕变性能好、制造成本相对较低,并且能形成结构复杂、尺寸精度较高的型芯产品,因此被广泛应用于涡轮叶片型芯、高尔夫球头等要求高的精密铸造中。但是氧化铝与强碱液或酸液的的化学反应能力均较弱,难以在酸液和碱液中迅速溶解而脱除,因此,以氧化铝为主要组分的氧化铝基陶瓷型芯的脱芯效果不是很理想,还不能完全满足工业生产的需要。所以,进行提高氧化铝基陶瓷型芯溃散性能的研究有着十分重要的意义。本文首先探讨了氧化铝基陶瓷型芯的三种制备方法,分析比较了三种制备方法所制得的型芯样品的常温抗折强度、高温残余强度和溶失速率等性能,最后得出用酚醛树脂作为粘结剂,通过压制成型的方法制备的型芯的溃散性最好。本研究通过正交实验的方法,着重研究了原料的组成,包括Si O2粒径大小、Si O2含量及Al2O3粒径大小对陶瓷型芯各基本性能的影响,分析了各因素对型芯常温抗折强度、高温残余强度和溶失速率影响的主次关系,发现Al2O3粒径大小对样品的常温抗折强度、高温残余强度和溶失速率都有较大影响。本文进一步研究Al2O3粒径大小对陶瓷型芯性能的影响,结果表明,在保证型芯常温抗折强度不小于8~10MPa的前提下,粒径200目型芯样品的溃散性能最好,其高温残余强度为3.0MPa,溶失速率达到1.22%min-1。另外,本文还研究了脱芯工艺的影响,探讨了脱芯方式(常压下直接碱煮和在反应釜中压力脱芯)、脱芯介质以及碱煮时间对型芯溶失性的影响,分析对比了两种脱芯方式的优劣,本文利用X射线衍射(XRD)、扫描电子显微镜(SEM)等手段分析了型芯的显微结构和相组成的变化,结果表明:气孔率越大的型芯样品的溶失速率也相应越大;样品在水中几乎不发生溶解,溶失速率为0,在碱液中的溶失速率最快可以达到3.20%min-1;碱煮时间不宜超过3h;在常压下直接碱煮会比在反应釜中更安全和更经济。
[Abstract]:Alumina based ceramic cores have high temperature resistance, good chemical stability, good creep resistance at high temperature, relatively low manufacturing cost, and can form core products with complex structure and high dimensional accuracy, so they are widely used in turbine blade cores. Golf head requires high precision casting. However, the ability of alumina to react with strong alkali or acid is weak, and it is difficult to dissolve and remove rapidly in acid and lye. The core removal effect of alumina based ceramic core with alumina as its main component is not ideal and can not fully meet the needs of industrial production. It is of great significance to improve the collapsibility of alumina based ceramic core. In this paper, three preparation methods of alumina based ceramic core are discussed. The flexural strength at room temperature, the residual strength at high temperature and the dissolution rate of the core samples prepared by three preparation methods were analyzed and compared. Finally, the phenolic resin was used as binder. The core prepared by pressing molding has the best collapsibility. In this study, the effects of the composition of raw materials, including Sio 2 particle size, Sio 2 content and Al2O3 particle size, on the basic properties of ceramic core were studied by orthogonal experiment. The influence of various factors on the flexural strength at room temperature, residual strength at high temperature and dissolution loss rate were analyzed. It was found that the particle size of Al2O3 affected the flexural strength at room temperature. The influence of the particle size of Al2O3 on the properties of ceramic core is studied. The results show that the flexural strength of the core is not less than 810MPa at room temperature. The particle size 200 mesh core has the best collapsibility, its high temperature residual strength is 3.0 MPA, and the dissolution stall rate is 1.22min-1. In addition, the influence of the core stripping process is also studied. In this paper, the effects of core stripping methods (direct alkali boiling under atmospheric pressure and pressure stripping in reactor, core removing medium and alkali boiling time) on core dissolution loss are discussed, and the advantages and disadvantages of two core stripping methods are analyzed and compared. In this paper, the microstructure and phase composition of the core are analyzed by means of X-ray diffraction and scanning electron microscope (SEM). The results show that the dissolution rate of the core sample increases with the increase of porosity. The sample hardly dissolves in water, the dissolution rate is 0, and the dissolution rate in alkali solution can reach 3.20min-1, the cooking time of alkali should not exceed 3h. it is safer and more economical to cook directly under normal pressure than in reaction kettle.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ174.1

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